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An extensive study of liquid propellant rocket engine test and flight history data has produced methods for advanced health monitoring currently under development for application to the Advanced Shuttle, National Aero-Space Plane, and other future propulsion systems. Advanced Health Monitoring is a systematic approach to instrumentation design and development, signal processing, and knowledge-based strategies to infer the operating status of any engine component or system. Properly implemented, Advanced Health Monitoring increases safety and the probability of mission success, significantly reduces turnaround time and maintenance cost, prolongs component life and reduces life-cycle cost.

Powertrain torsional vibration has become a subject of increasing concern for the heavy duty truck industry in recent years. This is due in part to truck and diesel engine developments, and to drivetrain system trends. A computer simulation is an effective tool in analyzing this problem. A powertrain vibration analysis program has been developed by the authors. It has been used extensively in the evaluation and optimization of powertrain system performance. In this paper, first the heavy duty powertrain is characterized as a vibrating system. Its natural frequencies, mode shapes and frequency response characteristics are reviewed. Second, the theory of torsional vibration and its application in the simulation are described. The drivetrain is described as a discreet model. An undamped modal analysis is given as an eigenvalue problem.

An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. This paper describes a hybrid (bimodal) system concept based on a proven, inherently safe solid fuel form for the high temperature reactor core operation and rugged planar thermionic energy converter for long-life steady state electric power production combined with NERVA-based rocket technology for propulsion. The integral system is capable of long-life power operation and multiple propulsion operations. At an optimal thrust level, the integral system can maintain the minimal delta-V requirement while minimizing the orbital transfer time. A trade study comparing the overall benefits in placing large payloads to GEO with the nuclear electric propulsion option shows superiority of nuclear thermal propulsion.

This paper presents classical control algorithms design for the solar array pointing system of the Space Station Freedom (SSF). This development is based on continuous, rigid body model of the solar array beta gimbal assembly (BGA) containing both linear and nonlinear dynamics due to various friction components. Optimum sets of controller parameters were obtained based on integral performance criteria through EASY5 simulations in the time domain. Classical sensitivity studies conducted in EASY5 indicated that the worst potential problem (possible system instability) is due to the variations in the electric motor dead-zone characteristics. After incorporation of an alternate static friction model, a Taguchi based tolerance design sensitivity study was conducted. Results indicated that the voltage variance, torque sensitivity constant and the motor resistance are the most important tolerances investigated with respect to integral square error (ISE).

The Dynamic Isotope Power System (DIPS) Demonstration Program is currently focused on the development of a standardized 2.5-kWe portable generator for multiple applications on the lunar or Martian surface. An optimum system configuration has been developed for the 2.5-kWe DIPS module that provides a system with a radiator area which is small and manageable without significantly impacting the system mass, efficiency, and technological risk. The 2.5-kWe DIPS module configuration was developed based on a systematic series of studies. Initially, technology breakpoints in the DIPS component and subsystem designs were identified. Based on the technology assessments, the maximum design temperature for the system was selected and various system and subsystem configurations were evaluated. Finally, the subsystem and system designs for the selected configuration were optimized using a detailed system design optimization computer code.

Significant advancements have been made in the development of lightweight, high performance, carbon-carbon heat pipes for space nuclear power applications. The subject program has progressed through the concept definition and feasibility analysis stages to the current test article component fabrication and assembly phase. This concept utilizes a carbon-carbon tube with integrally woven fins as the primary structural element and radiative surface, Nb-1Zr liners to contain a potassium working fluid, and welded end caps and fill tubes. Various tests have been performed in the development of suitable liner bonding techniques and in the assessment of material stability.

The early external active thermal control system (EEATCS) is designed to cool the U.S. Laboratory (USL), during early assembly stages of the International Space Station (ISS), to support assured early research (AER). The ISS is assembled on orbit over a period of about 5 years and over 40 stages. During later stages, about half way through the assembly, the USL is cooled by the external active thermal control system (EATCS), but that system is not available during early stages. To assure research, during early stages, the USL is cooled by the EEATCS; at a later stage, the USL cooling is switched to EATCS. During early stages, electric power is provided by the integrated truss segment (ITS) P6, which consists of photovoltaic (PV) arrays to convert sunlight into direct current power, an integrated equipment assembly (IEA) to support hardware required to store and condition electric power, and a long spacer to provide spacing between outboard power modules.

Activities within the Society of Automotive Engineers originating circa 1966 in Division 4 of the Iron and Steel Technical Committee Said the foundation for the contemporary approach to cumulative fatigue damage analysis and component lifetime predictive techniques. Previous and current activities of the Division 4 successor, the Fatigue Design and Evaluation Committee, have established the local stress-strain approach to ground vehicle durability as the industry-accepted methodology for fatigue design of critical components and structures subject to cyclic loading. This paper outlines the chronology of significant events and individuals within the Society of Automotive Engineers fatigue community that have advanced our comprehension, and offered solutions to the rather complex problem of durability by design.